Shuttlecock and method of making



Jan. 27, 1953 w, c, CARLTON 2,626,805

SHUTTLECOCK AND METHOD OF MAKING Filed June 25, 1950 I 2 SHEETSSHEET 1Inve nlor WEM A itorney Filed June 25, 1950 Jan. 27, 1953 w, c, CARLTON2,626,805

SHUTTLECOCK AND METHOD OF MAKING 2 Sl-lEETS-Sl-IEET 2 0 0O 23 I :0 00 a00 Fl 6. I1

Attorney Patented Jan. 27, 1953 UNITED STATES PATENT OFFICE SHUTTLECOCKAND METHOD OF MAKING William Charles Carlton, Hornchurch, EnglandApplication June 23, 1950, Serial No. 169,937 In Great Britain March 23,1950 '7 Claims. 1

This invention relates to shuttlecocks which might be used in the gameof badminton.

A difiiculty in shuttlecock manufacture hitherto has been to make theskirt, including the stems in one mass of material, that is, in aunitary piece. When feathers are used, about sixteen of them arerequired and a separate binding means is also provided. To overcome thedifficulty, it has previously been proposed that a skirt having innerand outer portions should be made complete from various sheets orfabrics, and then fixed to a cap. The term inner is used to designatethe skirt portion nearest to the cap, and outer is used to designate theskirt portion remote from the cap.

A successful shuttlecock, however, is of a fundamentally unsound shapefor manufacture from sheet materials unless the inner skirt portion isstrengthened by further thicknesses of material as the cap isapproached. This is expensive.

This invention is devoted to the design and manufacture of a shuttlecockwhich will have strength and delicacy where each is required, and yetmay be made extremely quickly, in its ultimate development, in oneintegral mass of material. A shuttlecock has therefore been inventedwhich has the performance characteristics reof the stems. A stem is anelongated body of] material extendin from the cap throughout the lengthof the skirt and forms a part of the latter.

The stem is thicker at the point where it leaves the cap than anymaterial between the stems in the outer skirt portion, and preferablyreduces in cross-sectional area as it approaches the trailing edge ofthe skirt. Each stem is integral with another stem, and preferably allthe stems of the shuttlecock are integral with each other.

This design may be produced by injection moulding of an end cap andthrough the end cap the stems in the form of a number of fine taperedrods, the injection being made at the big end of each rod, and armsbeing grown on each side of each red at a uniform distance from the bigend so that the injected material will reunite at the ends of these armsand thus form a set of ribs extending transversely of the stems integralwith each other and with said stems. A plurality of sets of ribs may bethus formed at spaced intervals. A suitable plastic material is used.The arms may be permitted to spread out in width by clearin the spacelocally between the male and female tools so that a plain vane or flightis made for the outer portion of the skirt. This is then provided withmany edges which create wind'resistance. These edges may be made bypiercing many gaps or holes after the completion of the mouldingoperation. If it is desired to incorporate the holes in the mouldingoperation this may be achieved by connecting the spaces left for thestems by a series of shallow canals about .1" apart instead of clearingthe space completely as was done for a skirt having a plain outerportion. The cap may be formed completely during the moulding operationby forcing the material around a substantially bowl-shaped space beforereaching the stems, or the stems may be merely united at their cap endsduring the moulding operation and the skirt then joined to a previouslyformed cap.

The material used in producing the first of these shuttlecocks was onein the polythene range because it combined a low specific gravity withhigh resistance to water absorption, an important point when ashuttlecock is stored under humid conditions. A 'mix was selected whichis resilient and flows freely at 190 degrees centigrade under pressure.The invention is not limited to this material, but it has been given asa guide to enable a satisfactory choice to be made. It will beunderstood that although injection moulding has been recommended as themethod of production, nevertheless the production of the basic idea isnot limited to this method.

In order that the invention may be readily understood and carried intoeffect, various examples will now be described with reference to theaccompanying drawings in which;

Fig. l is a fragmentary side elevation of a moulded shuttlecock inaccordance with this invention plus the injection pip.

Fig. 2 is the same, with the end-cap and in-' jection pip removed.

Fig. 3 is a fragmentary view of a developed blank for an alternativemethod of manufacture of the skirt of a shuttlecock.

Fig. 4 is a side elevation ofa modified form of the skirt of ashuttlecock plus the injection pip.-

Fig. 5 is a developed blank of the skirt of a shuttlecock as moulded inan alternative manner.

Fig. 6 is a sectional side elevation of a shuttlecock made from one massof material before removing the injection pip.

Fig. 7 is a fragmentary view of a modified form of shuttlecock skirt.

Fig. 8 is a fragmentary view of a further modified form of shuttlecockskirt.

Fig. 9 is a fragmentary view of a still further modified form ofshuttlecock skirt.

Fig. 10 shows a side elevation of another form of shuttlecock inaccordance with this invention.

Figs. 11 and 12 show fragmentary views of alternative forms of skirt.

Figs. 13 and 14 are sectional views twice full size as indicated at twopoints in Fig. 12.

Referring to Figure l, a pair of tools are made with spaces between themso that when they are mated in the normal operating manner for mouldingtools, and a hot plastic is forced through the aperture which eventuallycauses the pip I; the material flows via the space left for the end cap2 to each of the spaces left for the stems 3, and thence along each stemuntil it branches into the spaces left for the arms or ribs 4. Thematerial meets approximately in the middle of each of the ribs andmerges into one mass. The material continues to flow along the stemspaces up to and beyond and on leaving 5 the material continues throughthe length of the shuttlecock diminishing as it goes. It will thus beseen that openings 6 and l are formed simultaneously with the formationof the stems and ribs of the skirt.

When the shuttlecock is struck hard in play, a considerable load isimposed on the material be tween 2 and 5, and collapsing occurs in thisarea unless strength is provided. It has been established that provisionmust be made for considerable passage of air in this area such asthrough the openings 6 and 1, otherwise the reversal of the shuttlecockafter impact is poor. It has further been established that the qualityof a shuttlecock is improved if this area is reasonably rigid. Thestems, therefore, are thick at 2 and continue substantial between 2 and5 and then reduce in thickness as they continue to the trailing edge.The object of this is to make the outer portion of the skirt very lightas this is necessary for good shuttlecock performance.

The end-cap 2 is then cut off as shown in Figure 2, and we have ashuttlecock skirt which has the smaller area of its surface at 8compensated for by increased thickness in the stems, and as the spreadof the stem is increased beyond 9, the thickness is reduced. Thearrangement recommended is for the whole mass of the skirt and stems tobe made in one piece.

A somewhat inferior method, in that a separate jointing operation isnecessary, of combining stems with variation in thickness into one masscomprising at least two stems would be by compression moulding in theflat. The area is developed as shown in Figure 3, and the necessarystrength at 8A is provided by greater thickness between 8A and 9A thanis provided beyond 9A.

The method illustrated in Fig. 3 is carried forward in Fig. 5 whereinthin webs 23 are formed between the stems 22 adjacent their trailingedges. At the same time that the stems, ribs and webs are formed byproviding suitable spaces between the mould sections, the openings 24and 25 are formed due to the abutment of the mould sections in the areasof these openings. Relative- 1y small openings 26 may be punched orotherwise formed in the webs 23 to decre s we g 4 and increase drag asmore fully described hereinafter.

Returning now to the method illustrated in Figures 1 and 2, the idea isfurther developed in Figure 4. The moulded tools are modified so thatthe spaces between the stems are cleared to a depth as thin as possibleconsistent with strength and the ability of the material to run freely.The area l3l3-I1I1 is the result of a typical space so cleared, and whenthe material running down the stem spaces reaches this area it will growoutwards to form thin leaves which may weld together where the edges ofthe leaves from two stems meet, for instance, down the line l2--l4. Inpractice, with such thin leaves as these should be, it is more likelythat the material will merely butt, and the joint I2I4 may appear as acold shut. The point is not material so long as a series of areasI3l3'-H'-l1 are formed in the lower skirt of a shuttlecock, and that thematerial in these areas is very thin.

Referring now to Figure 6, the method suggested in Figure 1, anddeveloped in Figures 2 and 4, is now still further developed in Figure 6to include the cap of the shuttlecock. It will be seen that the end-cap2 in Figure 1 has been replaced by a cap 28 which is bowlshaped, andserves the same purpose as the end-cap 2 in facilitating the injectionmoulding operation, but in addition, replaces the usual cork cap, fittedto a badminton shuttlecock. After moulding, the pip 29 is removed.

That part of the invention which relates to the inducement of drag isnow reached. In Figure 7 is shown a fragment of a, typical outer portionof the skirt of a shuttlecock in which slits 3| have been made, and thematerial raised to form a number of small flaps 32, secured at theirtrailing edges, which interfere with the airstream 33 as it passes theoutside of the shuttlecock. When it is desired to reduce the weight ofthe lower skirt without reducing the diameter of the cone-like section,a number of small openings 34, 35, 36, 31 are made in the outer portionof the skirt as shown in Fig. 8. These serve three purposes, they reduceweight, increase surface drag, and change the air-flow over the trailingedge of the shuttlecock. It will be noticed that four different shapedopenings have been illustrated to indicate that almost any shape ofopening is effective so long as it is not too small in diameter. Anotherlimiting factor is that the openings must not be too close togetherotherwise strength and rigidity in the lower skirt is lost and irregularflight results. In Figure 9, the advantages illustrated in Figures '7and 8 are combined, the openings 38 being pierced to reduce weight andthe material 39 at the trailing edges of the openings being slightlyraised so as to interfere with the air stream.

Referring to Figure ID, a series of closely spaced ribs 40 have beenmade in the outer portion of the skirt by cutting a series of canals tojoin the spaces left in the tools for the stems 4 l, with flow to areasother than the canals being blanked off so that the resultingshuttlecock is complete with openings 42 direct off the mouldingoperation. This means that a shuttlecock complete with openings need behandled once only, i. e. to remove from the moulding machine and cut offthe injection pip.

Figs. 12, 13 and 14 illustrate the relative thickness of the stems andribs. and the decreasing cross sectional area of the stems in adirection toward the trailing edge of the shuttlecock. In this form, aweb 2| is formed in the area between the two outermost ribs and the stemportions adjacent thereto. The web is materially thinner than theadjoining ribs and stem portions, thus providing shallow air resistingpockets and also increasing to some extent the rigidity of the trailingedge portion of the skirt without materially increasing weight. Drag orair resistance is further increased by the openings 2| formed during themoulding operation between the other ribs in the outer portion of theskirt.

In Fig. 11, the space between adjacent stems in the outer portion of theskirt is partially filled by short broad ribs or leaves l6 projectinglaterally from the stems, two only of such short ribs being connected asshown at 20. The connecting rib adds strength and rigidity while theedges of the short ribs 15 increase air resistance.

I claim:

1. A method of making a shuttlecock consisting of forming a, cap open atone end by injecting a plastic into a mold, then forming a plurality ofdiverging stems by continuing the injection of the plastic to overflowthe same from the open end of the cap through a plurality of passagesdivergently extending from the cap, and then forming a set oftransversely extending ribs by further continuing the injection of theplastic to overflow the same laterally from said diverging passagesthrough communicating lateral passages.

2. A method of making a shuttlecock consisting of forming a cap open atone end by injecting a plastic into a mold, then forming a plurality ofdiverging stems by continuing the injection of the plastic to overflowthe same from the open end of the cap through a plurality of passagesdivergently extending from the cap, then forming a set of transverselyextending ribs by further continuing the injection of the plastic tooverflow the same laterally from said diverging passages throughcommunicating lateral passages, and then forming webs between the stemsand adjacent the ribs by still further continuing the injection of theplastic to overflow the same into shallow pockets extending laterallyfrom the diverging passages adjacent said lateral passages.

3. A method of making a shuttlecock consisting of forming a cap open atone end by injecting a plastic into a mold, and then forming a skirtprovided with openings by continuing the injection of the plastic tooverflow the same from the open end of the cap into passages divergentlyextending from the cap and also into a plurality of sets of transverselyextending pass-ages communicating with each other and with thedivergently extending passages.

4. A shuttlecock comprising a cap and a moulded skirt composed of ninner part adjacent the cap and an outer part remote from the cap, andincorporating stems extending from the cap and material between thestems in said outer part, the stems being thicker where they leave thecap than the material between the stems in said outer part and beingflared outwardly from the cap, and moulded integrally, and characterizedin that each stem has integral with it a plurality of ribs projectinglaterally from it in the area of the skirt remote from the cap.

5. A shuttlecock as in claim 4 and characterized in that at least one ofthe ribs makes a circumferential connection between the stems in thearea of the outer part of the skirt.

6. A shuttlecock a in claim 4 and characterized in that air spaces areleft between the ribs in the area of the outer part of the skirt.

7. A shuttlecock as in claim 4 and characterized in that the outer partof the skirt incorporates ribs with intervening plain vane portions.

WILLIAM CHARLES CARLTON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,620,922 Saunders Mar. 15, 19272,163,236 Collier June 20, 1939 2,192,180 Collier Mar. 5, 1940 2,212,079Saunders Aug. 20, 1940 2,218,593 Ushakoff Oct. 22, 1940 2,338,274 YancyJan. 4, 1944 2,354,790 Beck Aug. 1, 1944 FOREIGN PATENTS Number CountryDate 56,708 Denmark A. D. 1939 602,791 Great Britain A. D. 1948

